During the World Wars, pilots would blame gremlins for any mechanical failures in their planes.

Altimeter reading wrong, two-way radio not working right, steering shaft reversed, "eh, probably gremlins". This interpretation of one has a bat-like appearance. Its long claws allow it to dig into the metal hulls of whatever machine it wants. It has underarm wings that allow it to glide and control its descent from a plane in flight. The gremlin's protruding teeth pack a nasty wallop when it bites. Although small, even one gremlin can cause a nasty, machine-based accident.